Trouble 3.6

Scott Owner/Technician Iowa Posted   Latest   Edited  
Unsolved
Propulsion
2008 GMC Acadia 3.6L (LY7) 6-spd (6T75)

Will a bad cam phaser cause it to not start. I'm new to this engine help

0
Missing Tests
Craig Technician
Tennessee
Craig Default
 

If its jumped time it certainly will cause a no start but you can usually tell in how the engine turns over if its still in time. These engines are crap for timing chain problems...very very common.

+1
Default Ð Awarded
Scott Owner/Technician
Iowa
Scott Default
 

The chain around the idler gear and crank shaft was jumping . And now cranking it its got a clunking noise and tries to start but wont run . And yes i had timing plates and timed left cam and main chain and then backed it up to the other timing mark

0
Default Ð Awarded
Jason Technician
Illinois
Jason Default
 

What do you mean backed it up to the other timing mark ?

0
Default Ð Awarded
Scott Owner/Technician
Iowa
Scott Default
 

Two dots on oil pump one for right bank and other for left bank and crank and idler chain

0
Default Ð Awarded
Jason Technician
Illinois
Jason Default
 

sorry but not understanding you. Not questioning you but I am. Meaning you understanding theres unique marks for every chain? There’s no same marks for another chain if I said that correctly

0
Default Ð Awarded
Brian Diagnostician
Indiana
Brian Default
 

Yes on this engine you time the front bank to one set of marks and then turn the crank to a different sent of marks for the back bank. There are special tools to hold the cam shafts in both positions.

0
Default Ð Awarded
Brian Diagnostician
Indiana
Brian Default
 

The valve could be bent if the chain jumped time. Did you do a compression test on it? Also a leak down test of the cylinders. That would tell you what cylinder is your issue. Any codes?

+1
Default Ð Awarded
Scott Owner/Technician
Iowa
Scott Default
 

Compressing but not much with throttle open but if you pushed scrater valve could hear air release

0
Default Ð Awarded
Brian Diagnostician
Indiana
Brian Default
 

When you say compressing but not much what is the gage actually reading?

0
Default Ð Awarded
Scott Owner/Technician
Iowa
Scott Default
 

About 5 psi

0
Default Ð Awarded
Brian Diagnostician
Indiana
Brian Default
 

Is that just one cylinder or all cylinders one that bank? If it’s just one cylinder you have bent valves. It’s it’s all the cylinders in that bank it could be a stuck phaser. More then likely this vehicle needs a new engine. These things are very problematic.

0
Default Ð Awarded
Scott Owner/Technician
Iowa
Scott Default
 

All the bank but haven't check compression sence i did timing chains. Its got clunk when turning it over now wont start but trys to hit

0
Default Ð Awarded
Eric Owner/Technician
Wisconsin
Eric Default
 

If the vehicle came in with the crank and cams out of time, the timing chain jumped time, then you could have bent valves. It won't matter if you have the new timing chain parts in time, with bent valves you will have a no start and no compression. If I read one of your posts correctly the vehicle came in as a no start and had a clunk when you tried to turn it over. Sounds to me like it was…

0
Default Ð Awarded
Scott Owner/Technician
Iowa
Scott Default
 

Ok ill do compression test tomorrow thanks . But clunking started after installing timing chains

0
Default Ð Awarded
Eric Owner/Technician
Wisconsin
Eric Default
 

I wouldn't be rotating the engine any more until the timing is verified and you make sure the pistons aren't contacting the valves. Inspecting the tops of the pistons and looking at the valves with an inspection camera. No reason to do any more damage or to do potental damage by rotating the engine to do a compression test.

0
Default Ð Awarded
Scott Owner/Technician
Iowa
Scott Default
 

New timing chains are in time used plates and make sure it was timed right alread had it apart a second time

0
Default Ð Awarded
Scott Owner/Technician
Iowa
Scott Default
 

Will cam phasers on both intakes locked up and cam shaft journals and head bore eat up top side and cams all

0
Default Ð Awarded